1. Technical Field
The present invention relates to a semiconductor device and a manufacturing method for the same.
2. Related Art
In recent years, semiconductor devices in which a plurality of transistors are mounted together on the same semiconductor substrate for purposes such as changing electric current consumption according to an operating state of the apparatus have been attracting attention.
For example, JP-A-2010-16153 describes a semiconductor device in which a first MOS (Metal Oxide Semiconductor) transistor, a second MOS transistor, an LDMOS (Laterally Diffused MOS) transistor and the like are mounted together on a semiconductor substrate. In the semiconductor device described in JP-A-2010-16153, a P-type well and an N-type well are provided in a P-type semiconductor substrate, with the first MOS transistor being provided in the P-type well, and the second MOS transistor being provided in the N-type well. Also, in semiconductor devices in which a P-type well and an N-type well are provided in a P-type semiconductor substrate, a further N-type well may be provided in the semiconductor substrate, and a third MOS transistor may be provided at this N-type well, in order to support operating states of the apparatus, for example.
However, in the case where two N-type wells are provided in a P-type semiconductor substrate as described above, leakage current may occur between the two N-type wells when the potential that is applied to one of the N-type wells differs from the potential that is applied to the other N-type well.